Surendran, who is an opposition politician and the vice president of Anwar's National Justice Party (PKR), has pleaded not guilty.

The sedition charge has been immediately denounced by rights groups as a further betrayal of the government's promise to scrap the colonial-era law.

In 2012, Malaysian Prime Minister Najib Razak pledged to relax his government's authoritarian ways, as part of broader election promises.

But the Barisan Nasional government has continued to use the law regularly against its critics.

The opposition leader, who denies the charges, has accused the government of manipulating the courts in a long-term conspiracy to blacken his name and halt the growing momentum of the opposition alliance he leads.

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Anwar is currently out on bail.

"My lawyer has the right and the duty to speak of Najib's involvement in the ... conspiracy to jail me," Anwar said in a statement.

Mr Najib has previously admitted meeting with Anwar's sodomy accuser, Mohamad Saiful Bukhari Azlan, shortly before the original charges were filed. But he denies orchestrating the sodomy charges.

Mr Najib's office could not immediately be reached for comment.

Sodomy, even if consensual, is a crime in Muslim-majority Malaysia punishable by up to 20 years in jail.

Human Rights Watch criticised Surendran's sedition charge, which carries a maximum jail term of three years, as part of a "government campaign to systematically pursue its political opponents using trumped-up charges".

In a statement, the group's Asia deputy director Phil Robertson called Mr Najib's promise to scrap the sedition law "hollow rhetoric" meant to deceive the public.

"The Malaysia government's decision to charge N. Surendran with sedition today is yet another blatant example of a draconian law being used to violate freedom of expression and silence critics," he said.

"This is part of a clearly emerging Malaysian government campaign to systematically pursue its political opponents using trumped up charges under the Sedition Act.

"By engaging in legal harassment and persecution of opponents using a law that is an relic of colonial authoritarianism, Prime Minister Najib demonstrates that he apparently has no abiding commitment to either political moderation or human rights."

Mr Najib's office maintains it plans to replace the sedition law but has given no timeframe.